This is documentation for Mathematica 8, which was
based on an earlier version of the Wolfram Language.
View current documentation (Version 11.2)

Options for Expression Input and Output

typical default value
AutoIndentAutomaticwhether to indent after an explicit Return character is entered
DelimiterFlashTime0.3the time in seconds to flash a delimiter when a matching one is entered
ShowAutoStylesTruewhether to show automatic style variations for syntactic and other constructs
ShowCursorTrackerTruewhether an elliptical spot should appear momentarily to guide the eye if the cursor position jumps
ShowSpecialCharactersTruewhether to replace by a special character as soon as the is entered
ShowStringCharactersTruewhether to display when a string is entered
SingleLetterItalicsFalsewhether to put single-letter symbol names in italics
ZeroWidthTimesFalsewhether to represent multiplication by a zero width character
InputAliases{}additional name aliases to allow
InputAutoReplacements{"->"->"→",...} strings to automatically replace on input
AutoItalicWords{"Mathematica",...}words to automatically put in italics
LanguageCategory"NaturalLanguage"what category of language to assume a cell contains for spell checking and hyphenation

Options associated with the interactive entering of expressions.

The option SingleLetterItalics is typically set whenever a cell uses TraditionalForm.
Here is an expression entered with default options for a StandardForm input cell.
Here is the same expression entered in a cell with SingleLetterItalics and ZeroWidthTimes.
Built into Mathematica are a large number of aliases for common special characters. InputAliases allows you to add your own aliases for further special characters or for any other kind of Mathematica input. A rule of the form "name"->expr specifies that should immediately be replaced on input by expr.
Aliases are delimited by explicit Esc characters. The option InputAutoReplacements allows you to specify that certain kinds of input sequences should be immediately replaced even when they have no explicit delimiters. By default, for example, is immediately replaced by . You can give a rule of the form to specify that whenever seq appears as a token in your input, it should immediately be replaced by rhs.
"NaturalLanguage"human natural language such as English
"Mathematica"Mathematica input
"Formula"mathematical formula
Nonedo no spell checking or hyphenation

Settings for LanguageCategory to control spell checking and hyphenation.

The option LanguageCategory allows you to tell Mathematica what type of contents it should assume cells have. This determines how spelling and structure should be checked, and how hyphenation should be done.
typical default value
StructuredSelectionFalsewhether to allow only complete subexpressions to be selected
DragAndDropFalsewhether to allow drag-and-drop editing

Options associated with interactive manipulation of expressions.

Mathematica normally allows you to select any part of an expression that you see on the screen. Occasionally, however, you may find it useful to get Mathematica to allow only selections which correspond to complete subexpressions. You can do this by setting the option StructuredSelection->True.
Here is an expression with a piece selected.
With StructuredSelection->True only complete subexpressions can ever be selected.
Unlike most of the other options here, the DragAndDrop option can only be set for the entire front end, rather than for individual cells or cell styles.
GridBox[data,opts]give options that apply to a particular grid box
StyleBox[boxes,opts]give options that apply to all boxes in boxes
Cell[contents,opts]give options that apply to all boxes in contents
Cell[contents,GridBoxOptions->opts]give default options settings for all GridBox objects in contents

Examples of specifying options for the display of expressions.

As discussed in "Textual Input and Output", Mathematica provides many options for specifying how expressions should be displayed. By using StyleBox you can apply such options to collections of boxes. But Mathematica is set up so that any option that you can give to a StyleBox can also be given to a complete Cell object, or even a complete Notebook. Thus, for example, options like Background and LineIndent can be given to complete cells as well as to individual StyleBox objects.
There are some options that apply only to a particular type of box, such as GridBox. Usually these options are best given separately in each GridBox where they are needed. But sometimes you may want to specify default settings to be inherited by all GridBox objects that appear in a particular cell. You can do this by giving these default settings as the value of the option for the whole cell.
For most box types named , Mathematica provides a cell option that allows you to specify the default options settings for that type of box. Box types which take options can also have their options set in a stylesheet by defining the style. The stylesheets which come with Mathematica define many such styles.